SALT LAKE CITY — President Barack Obama unveiled an ambitious plan to address climate change, building on his initiatives to embrace more dependence on renewable energy, increase fuel economy for vehicles and to cut carbon pollution from power plants.

In a Tuesday speech under sweltering heat at Georgetown University, Obama declared the debate on climate change over and stressed the time for action is now.

"The question is not whether we need to act," he said. "The question now is whether we will have the courage to act before it is too late."

Obama said the science backing climate change is resoundingly in, with 97 percent of the scientific community on board and no longer quibbling about its debilitating impacts.

"Those who are feeling the effects of climate change don't have time to deny it," he said, pointing to firefighters overwhelmed by cataclysmic "mega" fires that are wiping out entire neighborhoods and farmers' crops being battered by both floods and fire.

• Doubling renewable energy generation by 2020 by accelerating permitting for utility-scale projects on federal lands, and improving the electronic grid through streamlining the siting and review process for transmission projects.

• Expanding the "Better Buildings Challenge" from commercial and industrial buildings to multifamily housing, with a goal to become at least 20 percent more energy-efficient by 2020.

• Establishing a new goal that the federal government will consume 20 percent of its energy from renewable sources by 2020, more than double the current goal of 7.5 percent.

• Reducing wildfire risk with the launch of the Western Watershed Enhancement Partnership, a pilot effort in five Western states to remove extra brush and other flammable vegetation around critical areas such as reservoirs.

Obama's plan also includes the expansion of fuel-economy standards finalized in 2011 for heavy-duty vehicles to make them more fuel efficient.

The standards build on what the Obama administration says is the implementation of the toughest fuel-economy standards for passenger vehicles in U.S. history, requiring an average of 54.5 mpg by 2025.

The Environmental Protection Agency is also considering a move to Tier 3 standards on vehicles and light trucks — a standard which would require a two-thirds reduction in the sulfur content of gasoline and bigger catalytic converters with heat pumps to avoid “cold start” emission releases.

Earlier this month, the Utah Air Quality Board endorsed the move and was followed by Utah Gov. Gary Herbert last week when he sent a letter to the EPA.

“This is really a strategy to help Utah achieve better air quality statewide and could well do more for our region’s health and environment than other efforts,” Herbert's letter said. "This effort to reduce emissions can make a meaningful difference in Utah’s unique circumstances.”

High in Obama's crosshairs for their role in greenhouse gas emissions are the nation's power plants, which he said face no federal standard to reduce their carbon output.

"There is no federal rule to prevent power plants from reducing as much carbon pollution as they want," he said, noting they account for one-third of all domestic greenhouse gas emissions.

An emissions inspection is conducted on a vehicle in Salt Lake County Tuesday, June 25, 2013. (Jeffrey D. Allred, Deseret News)

HEAL Utah, a grassroots environmental activist group, took Obama's speech on climate change as an opportunity to pounce on Rocky Mountain Power, saying action is needed in Washington, D.C., because of the utility company's lack of transitioning to a "green energy" economy.

“Rocky Mountain Power has failed in any significant way to clean up what is the West’s most polluting energy portfolio,” said Christopher Thomas, HEAL’s executive director. “The damaging health and environmental impacts of coal pollution have never been clearer, yet Rocky Mountain Power continues to bury its head in the sand.”

The organization pointed to a report commissioned by the Natural Resources Defense Council demonstrating that among the top 10 biggest power producers in the West, PacifiCorp ranks second worst for carbon dioxide emission rate, worst for nitrogen oxides emission rate, worst for sulfur dioxide emission rate and second worst for mercury emission rate.

HEAL Utah added that Rocky Mountain Power has "utterly failed" to invest in clean, green energy and has no plans to add any new green energy projects until at least 2024.

Spokeswoman Maria O'Mara, while stressing the company has no official comment on Obama's climate change plan, said Rocky Mountain Power, as part of PacifiCorp, has 1,400 megawatts of wind resources in its service territory, most of it brought online in the past 10 years.

"We are the largest regulated utility owner of wind resources in the West and the second largest in the nation," O'Mara said.